Ring binder



FIG. 1 is a perspective view of a ring binder of the present invention, the dotted line structure forming no part of the invention;

FIG. 2 is a top plan view thereof, the dotted line structure forming no part of the invention;

FIG. 3 is a right side view thereof (the left side being identical), the dotted line structure forming no part of the invention; and,

FIG. 4 is an end view thereof (the other end being identical). 

The ornamental design for a ring binder, as shown and described. 